Bill O'Reilly all but barked at Geraldo Rivera on "The O'Reilly Factor" Tuesday night over the mustachioed one's claim that Casey Anthony was a "good mother."

"Bull!" countered O'Reilly at Rivera, who was reporting live from outside the Florida trial at which Anthony was found not guilty of causing the 2008 death of her 2-year-old daughter, Caylee. "This is so much bull I can't stand it!"

"How does a good mother go to a wet body contest when her baby is missing?" queried O'Reilly.

Rivera unleashed a torrent of possible (though highly sensationalistic) reasons, including "maybe her brain was so distorted from years of abuse that she can't think straight" and "maybe she's mentally ill" and "what if this — what if it's the baby's daddy?"

O'Reilly was having none of it.

"Stop with the what ifs, Geraldo" said O'Reilly, "let's just go with the record."

A broken record, perhaps? The sparring on Fox News just added more Casey Anthony babble to the incessant coverage of the trial by cable news networks, which hit a fever pitch on Tuesday night.

The Headline News hawk, just 11 short years into the 2000s, has already billed the Anthony case as "The Trial of the Century" — something that will surely be amended when the next big murder mystery comes along.

Keith Olbermann, to his credit, sat this one out.

"And if nobody's clear on this: No trial will be covered on tonight's 'Countdown,'" tweeted the Current TV anchor Tuesday afternoon. "Except the various trials of my patience."

While she got off on the most serious charges, Anthony was convicted on four counts of lying to police officers. She will be sentenced on Thursday at 9 a.m. ET.